91 lines
3.0 KiB
TypeScript
91 lines
3.0 KiB
TypeScript
import { ITransport, WebSocketTransport, ServerSentEventsTransport, LongPollingTransport } from "./Transports"
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import { HttpClient } from "./HttpClient"
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enum ConnectionState {
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Disconnected,
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Connecting,
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Connected
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}
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export class Connection {
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private connectionState: ConnectionState;
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private url: string;
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private queryString: string;
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private connectionId: string;
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private transport: ITransport;
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private dataReceivedCallback: DataReceived = (data: any) => { };
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private connectionClosedCallback: ConnectionClosed = (error?: any) => { };
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constructor(url: string, queryString: string = "") {
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this.url = url;
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this.queryString = queryString;
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this.connectionState = ConnectionState.Disconnected;
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}
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async start(transportName: string = 'webSockets'): Promise<void> {
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if (this.connectionState != ConnectionState.Disconnected) {
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throw new Error("Cannot start a connection that is not in the 'Disconnected' state");
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}
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this.transport = this.createTransport(transportName);
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this.transport.onDataReceived = this.dataReceivedCallback;
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this.transport.onError = e => this.stopConnection();
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try {
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this.connectionId = await new HttpClient().get(`${this.url}/getid?${this.queryString}`);
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this.queryString = `id=${this.connectionId}`;
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await this.transport.connect(this.url, this.queryString);
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this.connectionState = ConnectionState.Connected;
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}
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catch(e) {
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console.log("Failed to start the connection.")
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this.connectionState = ConnectionState.Disconnected;
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this.transport = null;
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throw e;
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};
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}
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private createTransport(transportName: string): ITransport {
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if (transportName === 'webSockets') {
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return new WebSocketTransport();
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}
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if (transportName === 'serverSentEvents') {
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return new ServerSentEventsTransport();
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}
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if (transportName === 'longPolling') {
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return new LongPollingTransport();
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}
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throw new Error("No valid transports requested.");
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}
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send(data: any): Promise<void> {
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if (this.connectionState != ConnectionState.Connected) {
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throw new Error("Cannot send data if the connection is not in the 'Connected' State");
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}
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return this.transport.send(data);
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}
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stop(): void {
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if (this.connectionState != ConnectionState.Connected) {
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throw new Error("Cannot stop the connection if it is not in the 'Connected' State");
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}
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this.stopConnection();
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}
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private stopConnection(error?: any) {
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this.transport.stop();
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this.transport = null;
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this.connectionState = ConnectionState.Disconnected;
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this.connectionClosedCallback(error);
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}
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set dataReceived(callback: DataReceived) {
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this.dataReceivedCallback = callback;
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}
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set connectionClosed(callback: ConnectionClosed) {
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this.connectionClosedCallback = callback;
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}
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} |